Shared-Use Vehicle Services for Sustainable Transportation: Carsharing, Bikesharing, and Personal Vehicle Sharing Across the Globe

Susan Shaheen, PhD and Adam Cohen

This special issue of the International Journal of Sustainable Transportation highlights developments in shared-use vehicle research, in particular carsharing, public bikesharing, and personal vehicle sharing. Since the mid-1980s, shared-use vehicle services have gained momentum across the world. Developments include a range of operational models—private, non-profit, and governmental ventures; advanced technology; worldwide entry and growth; collaboration and competition; and increased activity by auto rental companies and automakers.

Innovative Mobility Carsharing Outlook – Fall 2012

Susan A.Shaheen, Ph.D. and Adam Cohen

As of October 2012, carsharing was operating in 27 countries and five continents, with an estimated 1,788,000 members sharing over 43,550 vehicles. Carsharing was planned in seven additional countries worldwide. North America remains the largest carsharing region in terms of membership, with 50.8% of worldwide members and 36% of all fleets deployed. Europe, which has lower member-vehicle ratios, accounts for 38.7% of members and 47.0% of fleets deployed. 

Truck Parking and Traffic on I-5 in California: Analysis of a Clipboard Survey and Annual Average Daily Traffic Data

Elliot Martin, PhD and Susan Shaheen, PhD

Truck parking is a major problem on I-5 in California as truck drivers regularly encounter parking that is at or near capacity, particularly when searching for overnight parking. This creates safety hazards for truck drivers as well as the traveling public. This study reports on the results of a clipboard survey of truck drivers (N = 85) on I-5 in California in Spring 2012.

Zero- and Low-Emission Vehicles in U.S. Carsharing Fleets: Impacts of Exposure on Member Perceptions

Susan Shaheen, PhD, Elliot Martin, PhD, and Apaar Bansal

The California Zero-Emission Vehicle (ZEV) Mandate, adopted in 1990, was aimed at increasing the sale and dissemination of low- or zero-emission vehicles throughout the California auto market. ZEVs include plug-in hybrid vehicles (PHVs) and all-electric vehicles (EVs). In an attempt to accelerate the exposure of ZEVs in the general population, in 2001, additional credits were allotted to automakers in return for placing ZEVs into transportation networks, such as carsharing fleets. This policy is set to end in 2018.

Impacts of car2go on Vehicle Ownership, Modal Shift, Vehicle Miles Traveled, and Greenhouse Gas Emissions: An Analysis of Five North American Cities

Elliot Martin, PhD and Susan Shaheen, PhD

Carsharing is the shared use of a vehicle fleet by members for tripmaking on a per trip basis. There are four forms of carsharing in North America today: 1) roundtrip, 2) one-way, 3) peer-to-peer, and 4) fractional. In roundtrip carsharing, members begin and end a trip at the same vehicle location and typically pay for use by the hour, mile, or both. One-way carsharing enables members, who pay by the minute, to begin and end a trip at different locations—either throughout a free floating zone or stationbased model with designated parking locations.

Dynamic Ecodriving in Northern California: A Study of Survey and Vehicle Operations Data from an Ecodriving Feedback Device

Elliot Martin, Ph.D, Kanok Boriboonsomsin, Ph.D, Nelson Chan, Nigel Williams, Susan Shaheen, Ph.D, and Matthew Barth, Ph.D

Ecodriving describes the behavioral modifications that drivers can make to improve their fuel economy. Dynamic ecodriving comprises the use of real-time feedback information that informs the driver of vehicle performance. This study evaluates the performance of an aftermarket real-time feedback device that reported instantaneous fuel economy to drivers while driving. Study participants (N = 18) drove with the device for two months. During the first month, the device provided no feedback, but collected data on driving activity.

Trends and Trajectory of Shared Mobility

Susan Shaheen, PhD


• Carsharing: History, Worldwide and North America Growth, Personal Vehicle Sharing, and Autonomous Vehicles

• Public Bikesharing: History, Worldwide and North American Growth, and North American Operations

• Ridesharing / Ridematching: History and Current Status 

Innovative Mobility Carsharing Outlook – Summer 2013

Susan Shaheen, PhD and Adam Cohen

The recent acquisitions of IGO CarSharing by Enterprise Holdings in May 2013 and Zipcar by the Avis Budget Group in January 2013 continues a trend of mergers and acquisitions in North American “classic” carsharing (or roundtrip, short-term vehicle access). This trend began in the early 2000s with the Flexcar acquisition of CarSharing Portland in 2001 and the merger of Zipcar and Flexcar in 2007. Mergers and acquisitions again became an industry hallmark with the Enterprise Holdings’ acquisition of PhillyCarShare in 2011 and their acquisition of Mint Cars On-Demand in 2012. 

Applying Integrated ITS Technologies to Carsharing System Management: A CarLink Case Study

Susan Shaheen, PhD and Kamill Wipyewski

Carsharing is the short-term use of a shared vehicle fleet by authorized members. Since 1998, U.S. carsharing services have experienced exponential growth. At present, there are 13 carsharing organizations. Over the past three years, electronic and wireless technologies have been developed that can facilitate carsharing system management in the U.S., improve customer services, and reduce program costs. This paper examines the U.S.

Peer-to-Peer Carsharing: Exploring Public Perception and Market Characteristics in the San Francisco Bay Area, California

Ingrid Ballús Armet, Susan Shaheen, PhD, Kelly Clonts, and David Weinzimmer

Peer-to-peer carsharing is an innovative approach to vehicle sharing in which vehicle owners temporarily rent their personal automobiles to others in their surrounding area. Peer-to-peer carsharing belongs to the larger sharing economy, an economic model premised on the notion of collaborative consumption as opposed to ownership. This study examined public perception of peer-to-peer carsharing and potential market characteristics through an intercept survey conducted in the San Francisco Bay Area, California.